Nature Of Operations (Details) (USD $) In Millions	0 Months Ended		9 Months Ended								1 Months Ended		3 Months Ended	9 Months Ended
	Aug. 03, 2010 Kroll Divestiture [Member]	Sep. 30, 2011 Kroll Divestiture [Member]	Sep. 30, 2011 Acquisition Haake Companies Inc [Member]	Sep. 30, 2011 Acquisition HSBC Insurance Brokers Ltd [Member]	Sep. 30, 2011 Acquisition Bostonian Group [Member]	Sep. 30, 2011 Acquisition Trion [Member]	Sep. 30, 2011 Acquisition SBS [Member]	Sep. 30, 2011 Acquisition RJF [Member]	Sep. 30, 2011 Acquisition Hampton Roads [Member]	Sep. 30, 2011 Acquisition Evaluation Associates LLC [Member]	Jul. 31, 2010 Acquisition Innovative Process Administration [Member]	Aug. 31, 2010 Acquisition ORC Worldwide [Member]	Mar. 31, 2011 Acquisition Hammond Associates [Member]	Sep. 30, 2011 Acquisition Thomas Rutherfoord Inc [Member]	Sep. 30, 2011 Prescott Pailet Benefits [Member]	Sep. 30, 2011 Boston Office of Kinloch Consulting Group Inc. [Member]	Sep. 30, 2011 Mahoney Associates [Member]
Proceeds from Divestiture of Businesses	$ 1,130
MMC sale date of Kroll to Altegrity		Aug. 03, 2011
Acquisition date			2010-03-31	2010-04-01	2010-04-01	2010-12-31	2010-12-31	2011-01-31	2011-02-28	2011-06-30	2010-07-31	2010-08-31	2010-03-31	2010-03-31	2011-07-31	2011-02-28	2011-07-31